The subject of the invention is a weighing chamber of an analytical balance, intended to protect a balance's weighing pan against air movement causing uncontrolled impact on the measurement accuracy.
A balance described in patent claim EP2088406 featuring a weighing chamber comprising glass parts, and sliding panels assembled on guide bars. The weighing chamber—a shield against air movement, is a cuboid shaped assembly mounted on top of the balance and fixed to its top section using fasteners positioned at corresponding openings in the balance and chamber. The ring-shaped fasteners feature notches for their meshing and fixing by rotation with application of wedge-shaped planes. The chamber consists of sliding top and side panels.
An anti-draft chamber of a balance, described by patent claim no. WO2009/101010, featuring removable panels located in a frame made of guides. The top section of one of the side panels features fastening pins assembled in the top guides, and on tilting it is removed by pulling upwards.
An invention U.S. Pat. No. 6,504,112 describes a balance featuring panels, where the side and top panels are slidable. Movement of these elements is enabled either manually or using motors. The characteristic feature is the design of the sliding side panels on horizontal cylindrical guides preventing skews when slidable.
Similarly, in the invention no. US2006185909, the side panels are slidable, while the top panel is lifted. This chamber features frame shaped structure components with the front and back elements featuring fragmental guiding grooves for sliding the panels, in particular in case of the back frame. The front and back panel are assembled permanently.
A balance, known from a description EP1195585, featuring a weighing section that borders a permanent, stationary part of a balance, and that is enclosed from at least one side with a wall panel, front panel and a top covering panel. At least one of the mentioned panels is sliding using a guiding assembly for opening and closing the weighing section. The guiding assemblies are in fact complex mechanisms, comprising shafts, toothed bars, gears, guide rolls, pulleys and cords. The characteristic feature of the chamber is that the grip design of at least one of the sliding panels is integrated with the guiding assembly and the grip design of the permanent wall panels is integrated with the stationary part. Each of the guiding assemblies locks and releases a corresponding panel using a lock-forming device that can be either locked or unlocked by the fastening mechanisms using simple application of force on the panel and/or the guiding assembly. A holder for lifting the balance, in other words a handle, is configured as a rail to the guiding element of the guiding assembly of the top covering panel.
In already known solutions of the chambers, guidance of the panels is often carried out in a technologically and structurally advanced manner. As in the invention U.S. Pat. No. 5,298,688, they are special two-wheeled rolls moving in encased rails, and the bottom guidance is ensured by a strip attached to the balance, and which are introduced into the grooves of the panels. Another solution, such as in EP0496952, where the panels are guided using toothed bar assembled on vertical shafts and gears, achieved exceptionally high level of complexity.
The purpose of the invention was a weighing chamber of a balance, featuring a simple design, enabling easy and comfortable means of disassembling its components. Additionally, designers' intention was to have a chamber with structure comprising minimum amount of connecting members of a technologically simple structure.
The weighing chamber, forms a superstructure of the weighing device and separates the weighing sections and protects it against ambient conditions impact, and in particular against air movement and air drafts. The weighing chamber has a shape of a transparent cuboid, comprising in its structure sliding panels and guides. The panels are assembled using at least one adjustable lock, locking at least one panel in a way that their release enables sliding movement and disassembling the other panels. The fastening lock forms a profiled element, preferably an angle bar shaped component assembled in a detachable manner to the horizontal structural beam, and preferably using a threaded connection. The chamber comprises two vertical columns assembled at the back corners of the chamber's interior which support the chamber structure comprising a horizontal beam for assembling the fastening lock and guides for holding and sliding the top and side panels using grips. The grips are preferably made of plastic, and fixed bilaterally on the panels, preferably using glue.
The structure of the chamber features a few elements joined with each other in a sequential manner, i.e. with a fixed assembling order, and their mutual stable connection is achieved by at least one blocking member—a lock with shaped bracket. Disassembling of the chamber is substantially enabled by this lock blocking access to all panels of the chamber. Removing the lock provides access to a determined disassembling order of other chamber components—the top panel, back panel and side panels, also in a simplest possible manner, i.e. by pulling them out of the positioning guides. Thus, the structure of the chamber partially resembles a logic toy, a labyrinth, which first assembling or disassembling requires short consideration. Such design of the chamber enables easy accessing its interior components, such as the weighing pan or chamber base panel, thus ensuring easy cleanness maintenance. The assembled chamber sufficiently protects the weighed object or substance against ambient conditions impact, and in particular against air movement, air drafts that in case of balances with high reading accuracy is indispensable for minimizing weighing errors. Consequently, this feature is ensured by simple structure of the sliding panels. The panels do not comprise any fixing elements, such as hinges, holders, etc. that often are causes for aperture occurrence and inexact contact of the adjacent panels. On the contrary, the preferable threaded connection of the angle bar shaped lock ensures appropriate level of mutual panels contact thus minimizing formation of opening or draftiness. Simple structure of the chamber features minimization of its components. The chamber does not comprise any hinges, swiveling members and similarly troublesome structural components increasing its operation unreliability while disassembling or assembling process, causing purposeless process extension. Additionally, unlike chambers featuring hinges or lifting components, the chamber according to the invention generates low costs related to its manufacturing and assembling. At the same time, the solidity of connections of chamber components is very high, and their operation is precise. The general impression of the chamber on balance operator is advantageous, due to its easy assembling and disassembling process carried out on basis of a single threaded component.